Breath actuated medicinal aerosol delivery apparatus

Abstract

An apparatus for delivering medicinal aerosol on-demand during patient inhalation wherein delivery of aerosol from a nebulizer (22) is optimized by synchronizing delivery to the inspiration of a patient (58)is disclosed. A control unit (32) monitors airway pressure and controls the flow of gas so that aerosol delivery is triggered by patient inhalation, in which event delivery continues for a predetermined time period which is adjustable by the user. The apparatus can be used with a mouthpiece (56), a face mask (66) without an integral exhalation valve, or a face mask (68) with an integral exhalation valve. The apparatus significantly increases the efficiency of delivery of medicinal aerosol by sensing a patient's inhalation and exhalation cycles and delivering aerosol only after a certain inhalation pressure is sensed following a certain previous exhalation pressure. These pressures, which are compared against predetermined thresholds, correspond to the actual patient breathing condition. By monitoring the patient's inhalation and exhalation in this manner, aerosol delivery is synchronized with the patient's breathing pattern. In this way, the apparatus prevents aerosol contamination of the environment without requiring an exhalation filter since aerosol is delivered to the patient only during inhalation. Exhalation is not obstructed since aerosol is not delivered during exhalation. Further, when it is desirable to use an exhalation filter to reduce the amount of exhalation gas discharged into the environment, the apparatus reduces occlusion occurring in the exhalation filter.

I claim: 
     
       1. A breath actuated apparatus for on-demand delivery of medicinal aerosol produced by a nebulizer containing medicament aerosolized by a flow of breathable gas, comprising: (a) a first wye, said first wye including first aerosol outlet means for delivering medicinal aerosol to a patient, said first wye including aerosol inlet means for receiving medicinal aerosol from a nebulizer, said first wye including air inlet means for receiving ambient air;   (b) a uni-directional inhalation valve coupled to said air inlet means;   (c) signalling means for providing an inhalation pressure signal representing inhalation of said patient and an exhalation pressure signal representing exhalation of said patient, said inhalation signal generated by said patient's inhalation airflow, said exhalation signal generated by said patient's exhalation airflow; and   (d) control means for sensing the magnitude of said inhalation and exhalation signals, said control means being responsive to a threshold inhalation pressure followed by a threshold exhalation pressure to permit delivery of said breathable gas to a nebulizer only when said threshold inhalation pressure is followed by said threshold exhalation pressure.   
     
     
       2. An apparatus as recited in claim 1, further comprising an aerosol delivery conduit coupled to said aerosol inlet means. 
     
     
       3. An apparatus as recited in claim 1, further comprising: (a) a second wye, said second wye including aerosol inlet means for receiving aerosol from said aerosol outlet means of said first wye, said second wye including aerosol outlet means for delivering aerosol to said patient, said second wye including exhalation gas outlet means for exhausting exhalation gases from said patient; and   (b) a uni-directional exhalation valve coupled to said exhalation gas outlet means.   
     
     
       4. An apparatus as recited in claim 3, further comprising a filter coupled to said exhalation valve. 
     
     
       5. An apparatus for controlling delivery of medicinal aerosol to a patient for inhalation therapy, comprising: (a) a first wye, said first wye including an aerosol inlet port, an air inlet port, and an aerosol outlet port, said aerosol inlet port including nebulizer coupling means for coupling to an aerosol nebulizer;   (b) a uni-directional inhalation valve coupled to said air inlet port;   (c) signalling means for providing an inhalation pressure signal representing inhalation of said patient and an exhalation pressure signal representing exhalation of said patient, said inhalation signal generated by said patient's inhalation airflow, said exhalation signal generated by said patient's exhalation airflow; and   (d) control means for sensing the magnitude of said inhalation and exhalation signals, said control means being responsive to a threshold inhalation pressure followed by a threshold exhalation pressure to permit delivery of said breathable gas to a nebulizer only when said threshold inhalation pressure is followed by said threshold exhalation pressure.   
     
     
       6. An apparatus as recited in claim 5, wherein said nebulizer coupling means comprises an aerosol delivery conduit coupled to said aerosol inlet port. 
     
     
       7. An apparatus as recited in claim 5, further comprising: (a) a second wye, said second wye including an aerosol inlet port coupled to said aerosol outlet port of said first wye, an aerosol outlet port, and an exhalation gas outlet port; and   (b) a uni-directional exhalation valve coupled to said exhalation gas outlet port.   
     
     
       8. An apparatus as recited in claim 7, further comprising a filter coupled to said exhalation valve. 
     
     
       9. An apparatus as recited in claim 8, wherein said nebulizer coupling means comprises an aerosol delivery conduit coupled to said aerosol inlet port, and said apparatus further comprises an aerosol nebulizer, said aerosol nebulizer including an aerosol outlet port coupled to said aerosol delivery conduit, said nebulizer including a gas supply port coupled to said control means, said control means coupled to a supply of breathable gas. 
     
     
       10. An on-demand aerosol delivery apparatus for controlling amounts of medicinal aerosol delivered to a patient during inhalation therapy, comprising: (a) a first wye, said first wye including an aerosol inlet port, an air inlet port, and an aerosol outlet port, said aerosol inlet port including nebulizer coupling means for coupling to an aerosol nebulizer;   (b) a uni-directional inhalation valve coupled to said air inlet port;   (c) an aerosol delivery conduit coupled to said aerosol inlet port, said aerosol deliver conduit including means for coupling to an aerosol nebulizer;   (d) signalling means for providing an inhalation pressure signal representing inhalation of said patient and an exhalation pressure signal representing exhalation of said patient, said inhalation signal generated by said patient's inhalation airflow, said exhalation signal generated by said patient's exhalation airflow; and   (e) control means for sensing the magnitude of said inhalation and exhalation signals, said control means being responsive to a threshold inhalation pressure followed by a threshold exhalation pressure to permit delivery of said breathable gas to a nebulizer only when said threshold inhalation pressure is followed by said threshold exhalation pressure.   
     
     
       11. An apparatus as recited in claim 10, further comprising: (a) a second wye, said second wye including an aerosol inlet port coupled to said aerosol outlet port of said first wye, an aerosol outlet port, and an exhalation gas outlet port; and   (b) a uni-directional exhalation valve coupled to said exhalation gas outlet port.   
     
     
       12. An apparatus as recited in claim 11, further comprising a filter coupled to said exhalation valve.